Process for forming a photocatalyst and oxidizing a cycloalkane

Abstract

Methods of preparing Pt/SrTiO3 photocatalysts comprising strontium titanate nanoparticles and platinum doped on a surface of the strontium titanate nanoparticles are described. Processes of oxidizing cycloalkanes to cycloalkanols and/or cycloalkanones by employing the Pt/SrTiO3 photocatalysts are specified. A method for recycling the photocatalyst is also provided.

The invention claimed is: 
     
       1. A process of forming a Pt/SrTiO 3  photocatalyst and oxidizing a cycloalkane to a cycloalkanol and/or a cycloalkanone, the process comprising:
 reacting strontium acetate with acetic acid to form a precursor composition; 
 adding titanium isopropoxide to the precursor composition and treating with ultrasound to form a second composition comprising strontium titanate nanoparticles; 
 drying the second composition and calcining in air to form a powder; 
 depositing platinum on the powder and reducing the platinum with hydrogen to form the Pt/SrTiO 3  photocatalyst in the form of strontium titanate nanoparticles having surface doped Pt; 
 wherein the platinum is present in an amount of 1.0-2.0 wt % relative to a total weight of the Pt/SrTiO photocatalyst; then 
 contacting a feed mixture comprising the cycloalkane and an oxidant with the Pt/SrTiO 3  photocatalyst thereby forming a reaction mixture; and 
 concurrently irradiating the reaction mixture with light thereby forming the cycloalkanol and/or the cycloalkanon. 
 
     
     
       2. The process of  claim 1 , wherein the feed mixture is contacted with the Pt/SrTiO 3  photocatalyst at a pressure of 0.5-2 atm. 
     
     
       3. The process of  claim 1 , wherein the feed mixture is contacted with the Pt/SrTiO 3  photocatalyst at a temperature of 40-80° C. 
     
     
       4. The process of  claim 1 , wherein the cycloalkane is present in the feed mixture at a concentration of 10-400 ppm. 
     
     
       5. The process of  claim 1 , wherein the oxidant is present in an amount of 5-30 vol. % relative to a total volume of the feed mixture. 
     
     
       6. The process of  claim 1 , wherein the Pt/SrTiO 3  photocatalyst is present at a concentration of 0.2-5.0 g of photocatalyst per liter of the reaction mixture. 
     
     
       7. The process of  claim 1 , wherein the oxidant is O 2 . 
     
     
       8. The process of  claim 1 , wherein the cycloalkane is cyclohexane, the cycloalkanol is cyclohexanol, and the cycloalkanone is cyclohexanone. 
     
     
       9. The process of  claim 1 ,
 wherein the reaction mixture is irradiated with light for 1 to 4 hours; and 
 wherein the process has a molar conversion of the cycloalkane to the cycloalkanol and/or cycloalkanone of greater than 95%. 
 
     
     
       10. The process of  claim 1 , further comprising:
 recovering Pt/SrTiO 3  photocatalyst after the irradiating to obtain a recovered Pt/SrTiO 3  photocatalyst; and 
 reusing the recovered Pt/SrTiO 3  photocatalyst, which maintains photocatalytic activity for at least 4 reaction cycles.